New York State Master Electrician Practice Exam

What must be connected to equipment grounding conductors in central vacuum outlet assemblies?

1. All live wires

2. Accessible non-current carrying metal parts

3. Metal raceways only

4. Data cables

The correct answer is: Accessible non-current carrying metal parts

In central vacuum outlet assemblies, connecting accessible non-current carrying metal parts to equipment grounding conductors is essential for ensuring safety and compliance with electrical codes. This practice prevents accidental electric shock by ensuring that any metal parts that could potentially become energized due to faults are properly grounded. By attaching the grounding conductors to these metal parts, any stray voltage or electrical faults will be directed safely to ground, minimizing the risk of electrical hazards for users. This grounding mechanism is a critical aspect of electrical safety because it helps establish a clear and effective path for fault current, facilitating the operation of overcurrent protection devices, such as circuit breakers, which can deactivate the circuit in case of a fault. The other options don't align with the grounding requirements: live wires do not require grounding but should be properly insulated and protected; metal raceways, while they can be grounded as a protective measure, are not the primary requirement and connecting them alone doesn't address safety fully; data cables, being non-current carrying at their terminals, don't necessitate a grounding connection in this context. Thus, the emphasis on grounding accessible non-current carrying metal parts is fundamental to ensuring the safety of the whole assembly.